Compressed air circuit breaker with a plurality of series connected breaking gaps



June 3, 1952 H. FORWALD 2,599,100

COMPRESSED AIR CIRCUIT BREAKER WITH A PLURALITY OF SERIES CONNECTED BREAKING GAPS Filed Jan. 17, 1948 2 sums-5mm 1 2 i 30- Res/5mm: f4 5 29 i 5 l2 1 I /7 i 5 o 23 8 6 2/ ,6 25 7 8 24 26 /O s L m vs 4 I 2 L \j j 711256 uqy min:

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YFORWALD June 3, 1952 2,599,100

COMPRESSED AIR CIRCUIT BREAKER WITH A PLURALITY 0F SERIES CONNECTED BREAKING GAPS 2 SHEETSSHEET 2 Filed Jan. 17, 1948 //1Y/7/0r f/aakon Tomm/a/ 5 X Wf/Wf Patented June 3, 1952 COMPRESSED AIR CIRCUIT BREAKER WITH A PLURALITY OF SERIES CONNECTED BREAKING GAP S Haakon Forwald, Valhalla, Ludvika, Sweden, assignor to Allmanna Svenska Elektriska Aktiebolaget, Vasteras, Sweden, a Swedish corporation Application January 17, 1948, Serial No. In Sweden May 29, 1942 1 Section 1, Public Law 690, August a, 1946 Patent expires May 29, 1962 7 Claims. (01. 200-145) This invention relates to compressed air circuit breakers with a plurality of series connected breaking gaps. i

In high tension circuit breakers, the breaking ability is increased by'providing the breakers with a plurality of breaking gaps; After breaking, the contacts or metallic members in contact with them are separated by air gaps under atmospheric pressure, and the creeping distance between these parts along the insulators carrying them must thus be dimensioned with respect to the voltage difference between-these'parts and the. insulating strength of the air under atmospheric pressure.

The present inventionhas for its object to provide a circuit breaker in which the outermost contacts of the series-comiected gaps are separated by a single insulating cylinder having an unbroken insulating external surface, the insulation between the contacts being efi'ected by air under pressure. p

According to the present invention, the movable contacts of the two breaking gaps are insulatingly carried within an insulating cylinder or within a space in communication with said cylinder, which space, after the interruption, remains filled with'air under pressure. The insulating distance between the contacts can therefore be considerably smaller than if they were separated by air under'atmospheric pressure.

On the accompanying drawing, Fig. 1 shows the circuit breaker according to the invention with two series connected breaking gaps, and Fig. 2 shows such a circuit breaker with four series connected breaking gaps.

In the form shown in Fig. 1, the bottom casmg I of the circuit breaker contains the extinguishing air valve 2 for controlling the supply of extinguishing compressed air, andv also contains a three-way air valve 3 for the control of the operating air. On this bottom casing I, there is also mounted a compressed air container 4, which carries the disconnecting switch insulator 5, which at its upper end carries the stationary contact 6 of the disconnecting switch. The other contact 1 of the disconnecting switch is pivoted in a support 8, attached to the metal casing I0, and is operated by the insulator 9, which serves as an operating shaft rotated by the operating mechanism of the breaker, which mechanism is not shown on the drawing.

The metal casing is carried by an insulator ll fastened to the bottom casing I, and the casing 10 in turn carries an insulating cylinder H, which is closed at its upper end by a cap I3,

through which a pipe II is passed. This pipe II is, at its lower end, shaped to form a stationary contact 15 for one of the breaking gaps of: the contact breaker. The stationary contact i6 01' the other breakinggap is attachedto or formed in the wall of the casing 10. A 7

The movable contacts H and I8 of the breaking gaps are of spherical form and are attached to rods I9 and 20 respectively, which rods are at theiropposite'ends attached to operating pistons 21" and'22 respectively, said pistons being move able in operating cylinders 23 and 24. These pistons 2|, 22' are provided with helical springs 25 and 26 respectively, which tend to press the movable contacts I'I, I8 against the corresponding stationary'contacts IS, IS respectively. The operating cylinder 24 is, through a passage or port 21, in communication with the cylinder 23 for the purpose explained below. The operating cylinder 24 is'also connected by a pipe line 2| with the three-way operating valve Si'or the operating air.

In the insulating cylinder l2 which is generally made of porcelain, an insulating tube 29, suitably made of an organic material, is provided, and this tube 29 is at its lower end closed by a perforated wall which serves as the support for the operating cylinders 23 and 24. These cylinders may, of course, be mounted in some other suitable or convenient manner directly to the in sulating cylinder l2 or to the insulator ,and the essential feature is that they are insulated from the parts 10 and M.

In order to increase the creeping distance between the casing l0 and the operating cylinders 23 and 24, the casing Ill may be attached to the insulating cylinder I 2 at a distance from itslower end, so that a part of this insulator projects into the casing Ill.

The said insulating tube 29 serves, on the one hand, to relieve the insulating cylinder I2 from the pressure exerted by the compressed air and the pressure generated by the arcs, but the same tube may, on the other band, also serve to carry a by-pass resistance 30, coupled in parallel with the contact gaps 15, ll. In operation. the circuit breaker actuates in the following manner:

When opening the circuit breaker, the exting'uishing valve 2 and operating valve 3 are simultaneously opened, and as soon as there is sufllcient pressure in the circuit breaker, the opcrating three-way valve 3 is turned so that the operating cylinders 23 and 24 are brought into communication with the atmosphere. The compressed air in the circuit breaker then acts on the operating piston 22 has passed the communia,

eating passage 21 between thefiYJinders 23.and

24, the compressed air in the,cirouitibreakeraacm on the lower side of the piston 2| so that the breaking gap I5, I1 is again closed by the action of the spring 25, due to the fact-that theair pressure is now equal on both sides of thepiston. The breaking gap I6, [8, however; remainsopen as long as the cylinder 24 is in communication with the atmosphere. As therbreakiingnz ap fl II has for its purpose only to interruptathe reduced current passing through .theby-pass resistance 30, the opening in the contact. iimaynas shown be considerably smaller than the opening in the contact l5, which means a considerable reduction in the consumption of compressed air.

':-When the circuit breaker hasthus been Opened, 1111 insulation against the voltage is obtained and the disconnectingiswitch 6,-1 may thenbe-opened by a. suitable. mechanism actuating .the insulattr g-shaft-v 9, .but not shown in. the drawing.

In closing the circuit breaker, compressed-air isr againdelivered .to the operating cylinders 23 and-:24, the breaking gap. t6, 1 8 being thenclosed vby the ,spring 25 acting -onthe piston 22.

:"Eigu2" shows-a circuit 'breakerwith 'fourseries connected breaking :gaps. :In this, figure,-c0rresponding parts are designated by the same referencenumerals as in Fig. 1, and corresponding parts-1m the two :lower breaking gaps, with their operating mechanisms are designated...by the same reference numerals as .the upper breaking gaps butewith an index applied vtoeach reference numeral.

.-'I his-,'form of the .circuit breaker difiers from thesiormshown at Fig. lin that four breaking gapsarepprovidedimthe casing 10,,instead of two, as in Fig. 1.

;-.T. h e-.three-way operating valve3.-isreplaced in-:F.ig... 2 by two operating-v yalyes 3 l 3| which valyes-are actuated-by a suitable gear 33. through the medium of .an insulating shaft 34. from :the operating insulating shaft =9. .Thesinner ends otthe. operating cylinders 24,24- are, through the operating valves. 3 l .3 l brought ,into. communi cation-with .the atmosphere through ,Jthe; pipes 3.5.1.355,

, Iclaim'asmyinvention:

1. A compressed air circuitbreaker comprising: .a-,.pair Hot-series connected; breaking-gaps, a metal-.1 zcasing-ivan- :insulating cylinder: carried by said casing, insulating means supporting ,-,the casing; .a metal top: cap. on said cylinder; a metal member dependingfromsaid capithe stationary contact of one of said gaps being located. at the lowersend: of said jdependingpmemberwand the stationary'contact-of fthe. other gap/being formed in; said metalcasing; and-insulating means,-sup- Porting themoveable; contacts; of said gaps .withiii) in the space formed by said metal casing and in- ;sulatir gcylinder. 7

4 2. A cempressed air contact breakeraccording to claim 1, comprising Operating pistons carrying two movable contacts, operating com- .pressedmair cylinders-for the pistons, and means wherebythe-pylindem are insulated from the said casing- 3. A compressed air contact breaker according -toclaiml, in the insulating cylinder has oneendsecured to said casing and its opposite end carrying'thejsaid depending member and the first stationary contact.

24...;A.zcompressediair contact breaker accordiiingito --claim 1, comprising an insulating tube .within,the,,said cylinder, operating compressed movable contacts, and means whereby said cylinders=and-pistons are carried by the end of the said insulating cylinder; secured to the said casing.

-5. A,-compresscd air circuit breakerl acoording to claim 1, comprising operating compressedair cylinders..:op rating.pistons m nted i ea d sy i ders aand c rr in th m vabl qce ta i rth saidrair oylinders-being-mounted within theiml t l as n andsaid d p nd n m m r rb nssin th formotametal cylinder.

1.6- --A.-compr ssediair :circuitbreak ria eerdina torclaim comprising operatin -.cemnmssemair cylinders- .and .-o rating,pi tons .mountedsi itb metal-c ing. nd ear-ryinsthe movable, cont cts. a pi line and three-wa wav fe .t ::5E .DD. of air through said pipe line to onepfi the cylinders. .anda communic n ;pa sgeelbetweenr two-cylinders to. .permit closing ofpone of .the aps wh t other remai pen :due to -t a pr ssure within th .m ta c sin -A- compressed .air .oircuit breakerawith a plurality of series connected, brcaking.; gaps,,,a metal casing enclosing said breaking gaps ipsulating cylinders secured tosaid casing,- the stati a y contacts oi a .-part,oi saidb reaking; gaps being carried. ,by; ,said insulatingcylinders, .the stationary contacts of ,the utenb eekine s n beingformed in: thewall of said casing, andthe movable contactsiofiallgthe breaking; gaps moun nw th isai met l veasin ea i bei :insulated.,therefrom.

rHAAKON- QRWALD fiihe:ren win zireierenees.rare Ofr-IBO IQLiDithB frlmpflthis patent:

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